Replacing mirrored data disks

[Robert Dukes_1]

We have got an rp7410 and two DS2300 Disk Arrays which are connected in Split bus mode to two separate PCI 4si RAID Cards. I have set up a 3 disk stripe on each array and am using LVM to mirror between the two arrays. Each 3 disk stripe gets presented to the OS as 1 logical drive, and I just LVM Mirror 1 LD to the other. I am performing some testing to validate that the system still works in the event of a disk failure. As a recovery method, Im going to use the following tasks:-

(1) Remove faulty disk
(2) Replace with New Disk
(3) Make Drive ONLINE using 'irm'
(4) vgcfgrestore -n /dev/rdsk/c?t?d?
(5) vgchange -a y
(6) vgsync

Does this sound OK?
Do I need to do a vg/lvreduce before I remove the faulty disk? Is this necessary based on the fact that the disk does not appear in ioscan as NO_HW, because it is part of a 3 disk array, the logical drive is still CLAIMED. I guess this is because the RAID card handles the fact that the disk has failed.

Any thoughts?

Many Thanks in advance for any help.

[Stf]

Hello,

here what i should do if I were you:

1. Remove faulty disk
2. Replace with new disk
3. ioscan -fnC disk
4. insf -e
5. pvcreate -f /dev/rdsk/c?t?d?
6. vgcfgrestore -n /dev/rdsk/c?t?d?
7. vgchange -a y
8. vgsync

Stf ;-)

[Steven E. Protter]

I think you are okay. The additional steps in the prior post are a good idea.

I've neer heard of step 3. insf -C should get the disk ready.

You may need to run pvcreate on it, but vgcfgrestore might handle it.

SEP

[Deoncia Grayson_1]

I had the same problem before and I followed the steps that STF just gave you... You want to do an ioscan first to make sure your server is seeing the new disk and is showing Claimed, then insf -e, vgcfgrestore, vgchange and vgsync. You should not have to break the mirror first, because right now your server is not using the disk that is showing No_Hardware.

[Geoff Wild · Accepted solution]

I learned this on a failed disk on a 7410 last year:

1) If the disk is completely "dead", such as if you run ioscan and status is "no_hw" then you can hot swap the disk online.

2) However in circumstances where the disk has not fully failed please do one of the following to avoid data corruption :

a) reduce mirror before replacing the disk
b) deactivate VG before replacing the disk
c) shutdown system to replace the disk


I needed to do step 2 - but didn't know - tried to hot swap the disk - and my swap got corrupted - had to go to single user mode to repair...

Rgds...Geoff